The present invention relates to liquid detergent compositions suitable for hand dishwashing comprising a polymeric suds volume and suds duration enhancer wherein the polymeric suds volume and suds duration enhancer comprises one or more quaternary nitrogen-containing monomeric units and/or zwitterionic monomeric units. The polymeric suds enhancers (suds boosters) suitable for use in the compositions of the present invention comprise have an average cationic charge density of 2.8 or less, preferably from about 0.01 to about 2.8, more preferably from about 0.1 to about 2.75, most preferably from about 0.75 to about 2.25 units per 100 daltons molecular weight at a pH of from about 4 to about 12. The present invention further relates to methods for providing enhanced suds volume and suds duration during hand washing.
Liquid detergent compositions which are suitable for hand dishwashing must satisfy several criteria in order to be effective. These compositions must be effective in cutting grease and greasy food material and once removed, must keep the greasy material from re-depositing on the dishware.
The presence of suds in a hand dishwashing operation has long been used as a signal that the detergent continues to be effective. However, depending upon the circumstances, the presence of suds or the lack thereof, has no bearing upon the efficacy of liquid detergents. Therefore, the consumer has come to rely upon a somewhat erroneous signal, the lack or absence of soap suds, to indicate the need for additional detergent. In many instances the consumer is adding an additional amount of detergent far in excess of the amount necessary to thoroughly clean the dishes. This wasteful use of detergent is especially true in hand dishwashing since the soiled cooking articles are usually cleaned in a xe2x80x9cwashing difficultyxe2x80x9d queue, for example, glasses and cups, which usually do not contact greasy food, are washed first, followed by plates and flatware, and finally pots and pans which contain the most residual food material and are usually, therefore, the xe2x80x9cgreasiestxe2x80x9d.
The lack of suds in the dishwater when pots and pans are usually cleaned, together with the visual inspection of the amount of residual food material on the cookware surface, typically compels the consumer to add additional detergent when a sufficient amount still remains in solution to effectively remove the soil and grease from the dishware or cookware surface. However, effective grease cutting materials do not necessarily produce a substantial amount of corresponding suds.
Accordingly, there remains a need in the art for liquid dishwashing detergents useful for hand washing dishware which have an enduring suds level while maintaining effective grease cutting properties. The need exists for a composition which can maintain a high level of suds as long as the dishwashing composition is effective. Indeed, there is a long felt need to provide a hand dishwashing composition which can be use efficiently by the consumer such that the consumer uses only the necessary amount of detergent to fully accomplish the cleaning task.
The present invention meets the aforementioned needs in that it has been surprisingly discovered that polymeric materials comprising one or more quaternary nitrogen-containing monomeric units and/or zwitterionic monomeric units have the capacity to provide liquid hand wash detergent compositions with extended suds volume and suds duration benefits. In other words, such polymeric materials are polymeric suds enhancers (suds boosters).
In one aspect of the present invention, liquid detergent compositions having increased suds volume and suds retention suitable for use in hand dishwashing, said compositions comprising:
a) an effective amount of polymeric suds enhancer (suds booster) wherein the polymeric suds enhancer comprises one or more quaternary nitrogen-containing monomeric units and/or zwitterionic monomeric units, preferably wherein said stabilizer comprises:
i) units capable of having a cationic charge at a pH of from about 4 to about 12;
provided that said suds enhancer has an average cationic charge density of 2.8 or less, preferably from about 0.01 to about 2.8, more preferably from about 0.1 to about 2.75, most preferably from about 0.75 to about 2.25 units per 100 daltons molecular weight at a pH of from about 4 to about 12;
b) an effective amount of a detersive surfactant; and
c) the balance carriers and other adjunct ingredients;
provided that a 10% aqueous solution of said detergent composition has a pH of from about 4 to about 12, is provided.
In another aspect of the present invention, liquid detergent compositions having increased suds volume and suds retention suitable for use in hand dishwashing, said compositions comprising:
a) an effective amount of polymeric suds enhancer (suds booster) wherein the polymeric suds enhancer comprises one or more quaternary nitrogen-containing monomeric units and/or zwitterionic monomeric units, preferably wherein said stabilizer comprises:
i) one or more units capable of having a cationic charge at a pH of from about 4 to about 12; and
ii) one or more units having one or more hydroxyl groups;
provided that said suds enhancer has a hydroxyl group density of about 0.5 or less, preferably from about 0.0001 to about 0.4; and
iii) optionally, one or more other monomeric units described hereinafter;
provided that said suds enhancer has an average cationic charge density of 2.8 or less; and
b) an effective amount of a detersive surfactant; and
c) the balance carriers and other adjunct ingredients;
provided that a 10% aqueous solution of said detergent composition has a pH of from about 4 to about 12, is provided.
In yet another aspect of the present invention, liquid detergent compositions having increased suds volume and suds retention suitable for use in hand dishwashing, said compositions comprising:
a) an effective amount of polymeric suds enhancer (suds booster) wherein the polymeric suds enhancer comprises one or more quaternary nitrogen-containing monomeric units and/or zwitterionic monomeric units, preferably wherein said stabilizer comprises:
i) one or more units capable of having a cationic charge at a pH of from about 4 to about 12; and
ii) one or more units having one or more hydrophobic groups, preferably the hydrophobic groups are selected from the group consisting of non-hydroxyl groups, non-cationic groups, non-anionic groups, non-carbonyl groups, and/or non-H-bonding group, more preferably the hydrophobic groups are selected from the group consisting of alkyls, cycloalkyls, aryls, alkaryls, aralkyls and mixtures thereof;
iii) optionally, one or more other monomeric units described hereinafter;
provided that said suds enhancer has an average cationic charge density of 2.8 or less;
b) an effective amount of a detersive surfactant; and
c) the balance carriers and other adjunct ingredients;
provided that a 10% aqueous solution of said detergent composition has a pH of from about 4 to about 12, is provided.
In still another aspect of the present invention, methods for providing increased suds retention and suds volume when hand washing dishware is provided.
These and other objects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All temperatures are in degrees Celsius (xc2x0 C.) unless otherwise specified. All documents cited are in relevant part, incorporated herein by reference.
Additional background on these compositions and methods is provided by PCT patent application Ser. Nos. PCT/US98/24853, PCT/US98/24707, PCT/US98/24699 and/or PCT/US98/24852 all incorporated herein by reference in their entirety.
All substituent groups in structural formulas in the Specification and Claims have the meaning defined in previous structural formulas in the Specification or Claims, respectively, unless indicated otherwise.
xe2x80x9cPolymeric suds enhancers (suds boosters)xe2x80x9dxe2x80x94xe2x80x9cPolymeric suds enhancers (suds boosters)xe2x80x9d as used herein means polymeric materials comprising one or more quaternary nitrogen-containing monomeric units which are cationic monomeric units and/or zwitterionic monomeric units. The different types of polymeric materials which fall within this definition are set forth below:
1) polymeric materials comprising cationic monomeric units (i.e., quaternary nitrogen-containing monomeric units alone or in combination with other cationic monomeric units);
2) polymeric materials comprising cationic and nonionic monomeric units (i.e., quaternary nitrogen-containing monomeric units alone or in combination with other cationic monomeric units, plus one or more nonionic monomeric units);
3) polymeric materials comprising cationic and anionic monomeric units (i.e., quaternary nitrogen-containing monomeric units alone or in combination with other cationic monomeric units, plus one or more anionic monomeric units);
4) polymeric materials comprising cationic, nonionic and anionic monomeric units (i.e., quaternary nitrogen-containing monomeric units alone or in combination with other cationic monomeric units, plus one or more nonionic monomeric units and one or more anionic monomeric units);
5) polymeric materials comprising zwitterionic monomeric units (i.e., zwitterionic monomeric units alone);
6) polymeric materials comprising zwitterionic and cationic monomeric units (i.e., zwitterionic monomeric units, plus one or more cationic monomeric units);
7) polymeric materials comprising zwitterionic and nonionic monomeric units (i.e., zwitterionic monomeric units, plus one or more nonionic monomeric units);
8) polymeric materials comprising zwitterionic and anionic monomeric units (i.e., zwitterionic monomeric units, plus one or more anionic monomeric units);
9) polymeric materials comprising zwitterionic, cationic and nonionic monomeric units (i.e., zwitterionic monomeric units, plus one or more cationic monomeric units and one or more nonionic monomeric units);
10) polymeric materials comprising zwitterionic, cationic and anionic monomeric units (i.e., zwitterionic monomeric units, plus one or more cationic monomeric units and one or more anionic monomeric units);
11) polymeric materials comprising zwitterionic, nonionic and anionic monomeric units (i.e., zwitterionic monomeric units, plus one or more nonionic monomeric units and one or more anionic monomeric units);
12) polymeric materials comprising zwitterionic, cationic, nonionic and anionic monomeric units (i.e., zwitterionic monomeric units, plus one or more cationic monomeric units, one or more nonionic monomeric units and one or more anionic monomeric units).
xe2x80x9cEffective amount of a polymeric suds enhancer (suds booster)xe2x80x9dxe2x80x94An xe2x80x9ceffective amount of a polymeric suds enhancer (suds booster)xe2x80x9d as used herein means a sufficient amount of the polymeric suds enhancer such that greasy and/or composite soils are removed and/or reduced from a substrate coming into contact with the polymeric suds enhancer.
The present invention relates to polymeric materials which provide enhanced suds duration and enhanced suds volume when formulated into liquid detergent compositions suitable for hand dishwashing. The polymeric material comprises one or more quaternary nitrogen-containing monomeric units and/or zwitterionic monomeric units, preferably wherein said polymeric material comprises an average cationic charge density of 2.8 or less, preferably from about 0.01 to about 2.8, more preferably from about 0.1 to about 2.75, most preferably from about 0.75 to about 2.25 units per 100 daltons molecular weight at a pH of from about 4 to about 12.
The liquid detergent compositions of the present invention comprise:
a) an effective amount of polymeric suds enhancer (suds booster) wherein the polymeric suds enhancer comprises one or more quaternary nitrogen-containing monomeric units and/or zwitterionic monomeric units, preferably wherein said stabilizer comprises:
i) units capable of having a cationic charge at a pH of from about 4 to about 12;
provided that said suds enhancer has an average cationic charge density preferably from about 0.01 to about 2.8, more preferably from about 0.1 to about 2.75, most preferably from about 0.75 to about 2.25 units per 100 daltons molecular weight at a pH of from about 4 to about 12;
b) an effective amount of a detersive surfactant; and
c) the balance carriers and other adjunct ingredients;
provided that a 10% aqueous solution of said detergent composition has a pH of from about 4 to about 12.
It is preferred that the polymeric suds enhancer (a) preferably further comprises one or more of the following:
ii) one or more units having one or more hydroxyl groups, provided that the polymeric suds enhancer has a hydroxyl group density of about 0.5 or less, preferably from about 0.0001 to about 0.4 as measured by the Hydroxyl Group Density Equation as outlined in greater detail below; and/or
iii) one or more units having one or more hydrophobic groups, preferably the hydrophobic groups are selected from the group consisting of non-hydroxyl groups, non-cationic groups, non-anionic groups, non-carbonyl groups, and/or non-H-bonding group, more preferably the hydrophobic groups are selected from the group consisting of alkyls, cycloalkyls, aryls, alkaryls, aralkyls and mixtures thereof.
It is desirable that the polymeric suds enhancer (a) further optionally, but preferably comprises one or more of the following:
iv) units capable of having an anionic charge at a pH of from about 4 to about 12;
v) units capable of having an anionic charge and a cationic charge at a pH of from about 4 to about 12;
vi) units having no charge at a pH of from about 4 to about 12; and
vii) mixtures of units (iv), (v), (vi), and (vii).
The following describe non-limiting examples of polymeric material which may be suitable for use in the liquid detergent compositions of the present invention.
The polymeric suds enhancers of the present invention are polymers which contain one or more quaternary nitrogen-containing monomeric units and/or zwitterionic monomeric units, and preferably further contain units capable of having a cationic charge at a pH of from about 4 to about 12, provided that the suds enhancer has an average cationic charge density of 2.8 or less, preferably from about 0.01 to about 2.8, more preferably from about 0.1 to about 2.75, most preferably from about 0.75 to about 2.25 units per 100 daltons molecular weight at a pH of from about 4 to about 12.
Preferably, the polymeric suds enhancers also include units capable of influencing the average cationic charge density of the quaternary nitrogen-containing or zwitterionic polymeric suds enhancers, preferably by decreasing the average cationic charge density of the quaternary nitrogen-containing or zwitterionic polymeric suds enhancers. Such units capable of influencing the average cationic charge density of the polymeric suds enhancers may, and preferably do, provide additional advantageous properties to the polymeric suds enhancers that increase their cleaning and/or suds boosting and/or suds retention properties. Further, such units may increase the interactions between the polymer, which is neutral or positively charged, and the soil which is negatively charged.
Additionally, the polymeric suds enhancer can be present as the free base or as a salt. Typical counter ions include, acetate, citrate, maleate, sulfate, chloride, etc.
Further, the polymeric suds enhancers of the present invention may be copolymers, terpolymers with random and/or repeating units, and/or block polymers such as di-, tri- and multi-block polymers.
For example a copolymer can be made from two monomers, G and H, such that G and H are randomly distributed in the copolymer, such as
GHGGHGGGGGHHG . . . etc.
or G and H can be in repeating distributions in the copolymer, for example
GHGHGHGHGHGHGH . . . etc.,
or
GGGGGHHGGGGGHH . . . etc.,
The same is true of the terpolymer, the distribution of the three monomers can be either random or repeating.
The polymeric suds enhancers (suds boosters) of the present invention preferably have a molecular weight in the range of from about 1,000 to about 2,000,000, preferably from about 5,000 to about 1,000,000, more preferably from about 10,000 to about 750,000, more preferably from about 10,000 to about 500,000, even more preferably from about 15,000 to about 300,000 daltons. Most preferably, the molecular weight of the polymeric suds enhancers is about 50,000 daltons or less.
The molecular weight of the polymeric suds enhancers of the present invention are determined using a Gel Filtration Chromatography (GFC) Method. Under this GFC Method, polymers are separated using GFC columns to determine molecular weight distribution. The molecular weight and distributions are measured through separation of the polymer species based on their hydrodynamic volumes. The hydrodynamic volume is related to molecular weight.
A detailed example of how the molecular weights of the polymeric suds enhancers of the present invention are determined follows. A 0.2% solution of the polymeric suds enhancer is first prepared in the aqueous mobile phase, 80/20 0.5M Ammonium Acetate/Methanol at pH 3.7. The solution is then injected onto the GFC column at 60xc2x0 C. and its absolute molecular weight and molecular weight distribution are calculated using both multi-angle laser light scattering (MALLS) and refractive index (RI) detection. Theoretical and practical examples of molecular weights determined by the GFC Method are found in: W. W. Yau, J. J. Kirkland, and D. D. Bly, Modern Size-Exclusion Liquid Chromatography, John Wiley and Sons, New York, 1979.
Any suitable quaternary nitrogen-containing group can be used as a monomeric unit of the polymeric suds enhancers of the present invention.
Nonlimiting examples of quaternary nitrogen-containing monomeric units suitable for the polymeric suds enhancers of the present invention include: 
wherein R1 is a hydrogen or a methyl group, preferably a methyl group; R2, R3 and R4 are linear or branched C1-C4 alkyl groups, preferably C1 groups; n represents an integer from 1 to 4, preferably 3; and Xxe2x88x92 represents a counterion which is compatible with the water-soluble or water-dispersible nature of the polymer, preferably Clxe2x88x92; 
wherein R5, R6, R7 and R8 are independently H, or a C1-C4 alkyl group, preferably a methyl group; k is an integer from 1 to 4, preferably 2; and Xxe2x88x92 represents a counterion which is compatible with the water-soluble or water-dispersible nature of the polymer, preferably Clxe2x88x92; and 
wherein R1 and R2 are independently H or a C1-C4 alkyl group, preferably a methyl group.
Any suitable zwitterionic group can be used as a monomeric unit of the suds enhancers of the present invention.
Nonlimiting examples of zwitterionic monomeric units suitable for the suds enhancers of the present invention include: 
wherein R9, R10 and R11 are independently H, or a C1-C4 alkyl group, preferably a methyl group; and m is an integer from 1 to 4, preferably 2.
Nonlimiting examples of zwitterionic monomeric units in accordance with the present invention include: 
In addition to the quaternary nitrogen-containing monomeric units and/or the zwitterionic monomeric units, the suds enhancers of the present invention may, and preferably do include one or more other monomeric units, other than quaternary nitrogen-containing monomeric units and zwitterionic monomeric units, such as amine oxide monomeric units, other cationic monomeric units, hydroxyl-containing monomeric units, hydrophobic monomeric units, hydrophilic monomeric units, anionic monomeric units and nonionic monomeric units.
The polymeric suds enhancers of the present invention may comprise an amine oxide monomeric unit having the formula: 
wherein R3 is an alkyl, hydroxyalkyl, or alkyl phenyl group or mixtures thereof containing from about 8 to about 22 carbon atoms; R4 is an alkylene or hydroxyalkylene group containing from about 2 to about 3 carbon atoms or mixtures thereof; x is from 0 to about 3; and each R5 is an alkyl or hydroxyalkyl group containing from about 1 to about 3 carbon atoms or a polyethylene oxide group containing from about 1 to about 3 ethylene oxide groups. The R5 groups can be attached to each other, e.g., through an oxygen or nitrogen atom, to form a ring structure.
A preferred class of amine oxide monomer units suitable for use as a polymeric suds volume and suds duration enhancer has the formula: 
wherein X is either O or N, n is an integer from 1 to 10, preferably from 2 to 6, more preferably 2 to 4.
For the purposes of the present invention the term xe2x80x9ccationic monomeric unitxe2x80x9d is defined as xe2x80x9ca moiety which when incorporated into the structure of the suds enhancers of the present invention, is capable of maintaining a cationic charge within the pH range of from about 4 to about 12. The cationic monomeric unit is not required to be protonated at every pH value within the range of about 4 to about 12.xe2x80x9d Non-limiting examples of monomeric units which comprise a cationic moiety, other than a quaternary nitrogen-containing moiety, include the cationic monomeric units having the formula: 
wherein each of R1, R2 and R3 are independently selected from the group consisting of hydrogen, C1 to C6 alkyl, and mixtures thereof, preferably hydrogen, C1 to C3 alkyl, more preferably, hydrogen or methyl. T is selected from the group consisting of substituted or unsubstituted, saturated or unsaturated, linear or branched radicals selected from the group consisting of alkyl, cycloalkyl, aryl, alkaryl, aralkyl, heterocyclic ring, silyl, nitro, halo, cyano, sulfonato, alkoxy, keto, ester, ether, carbonyl, amido, amino, glycidyl, carbanato, carbamate, carboxylic, and carboalkoxy radicals and mixtures thereof. Z is selected from the group consisting of: xe2x80x94(CH2)xe2x80x94, (CH2xe2x80x94CHxe2x95x90CH)xe2x80x94, xe2x80x94(CH2xe2x80x94CHOH)xe2x80x94, (CH2xe2x80x94CHNR4)xe2x80x94, xe2x80x94(CH2xe2x80x94CHR5xe2x80x94O)xe2x80x94 and mixtures thereof, preferably xe2x80x94(CH2)xe2x80x94. R4 and R5 are selected from the group consisting of hydrogen, C1 to C6 alkyl and mixtures thereof, preferably hydrogen, methyl, ethyl and mixtures thereof; z is an integer selected from about 0 to about 12, preferably about 2 to about 10, more preferably about 2 to about 6. A is NR6R7 or NR6R7R8. Wherein each of R6, R7 and R8, when present, are independently selected from the group consisting of H, C1-C8 linear or branched alkyl, alkyleneoxy having the formula:
xe2x80x94(R9O)yR10
wherein R9 is C2-C4 linear or branched alkylene, and mixtures thereof, R10 is hydrogen, C1-C4 alkyl, and mixtures thereof, y is from 1 to about 10. Preferably R6, R7 and R8, when present, are independently, hydrogen, C1 to C4 alkyl. Alternatively, NR6R7 or NR6R7R8 can form a heterocyclic ring containing from 4 to 7 carbon atoms, optionally containing additional hetero atoms, optionally fused to a benzene ring, and optionally substituted by C1 to C8 hydrocarbyl, and/or acetates. Examples of suitable heterocycles, both substituted and unsubstituted, are indolyl, isoindolinyl imidazolyl, imidazolinyl, piperidinyl pyrazolyl, pyrazolinyl, pyridinyl, piperazinyl, pyrrolidinyl, pyrrolidinyl, guanidino, amidino, quinidinyl, thiazolinyl, morpholine and mixtures thereof, with morpholino and piperazinyl being preferred.
Examples of the cationic unit of formula [I] include, but are not limited to, the following structures: 
A preferred cationic monomeric unit is 2-dimethylaminoethyl methacrylate (DMAM) having the formula: 
Nonlimiting examples of cationic monomeric units include: methyl chloride quats of dimethylethyl(meth)acrylates, methyl chloride quats of dimethylaminopropyl(meth)acrylamides, dimethyl- and diethylsulfate quats of dimethylaminoethyl(meth)acrylates, dimethyl- and diethylsulfate quats of dimethylaminopropyl(meth)acrylamides, and diallydimethylammonium halides, such as bromide and/or chloride salts.
The hydroxyl group density of a quaternary nitrogen-containing monomer- and/or zwitterionic monomer-containing polymeric suds enhancer of the present invention is determined by the following calculation.       Hydroxyl    ⁢          xe2x80x83        ⁢    Group    ⁢          xe2x80x83        ⁢    Density    =            [              Molecular        ⁢                  xe2x80x83                ⁢        Weight        ⁢                  xe2x80x83                ⁢        of        ⁢                  xe2x80x83                ⁢        Hydroxyl        ⁢                  xe2x80x83                ⁢        Group            ]              [              Total        ⁢                  xe2x80x83                ⁢        Monomer        ⁢                  xe2x80x83                ⁢        Molecular        ⁢                  xe2x80x83                ⁢        Weight            ]      
For example, the Hydroxyl Group Density of a quaternary nitrogen-containing monomer- and/or zwitterionic monomer-containing polymeric suds enhancer containing 2-dimethylaminoethyl methacrylate having a molecular weight of approximately 157 and hydroxyethylacrylate having a molecular weight of approximately 116 grams/mole, at a 1:3 mole ratio would be calculated as follows:       Hydroxyl    ⁢          xe2x80x83        ⁢    Group    ⁢          xe2x80x83        ⁢    Density    =                    [        17        ]                    [                              3            ⁢                          (              116              )                                +          157                ]              =    0.0337  
Preferably, the quaternary nitrogen-containing or zwitterionic polymeric suds enhancers of the present invention have a Hydroxyl Group Density of about 0.5 or less, preferably from about 0.0001 to about 0.4.